This invention deals with the type of valve for controlling dispensing of the contents from a flexible plastic bag of the type usually disposed in a box commonly made of corrugated board. The valve is carried by the spout of the bag and when the contents are to be dispensed, a suitable opening is formed in a wall of the box and the spout is manipulated into the opening and locked in dispensing position on that wall. Dispensing valves of this general type are disclosed in U.S. Pat. Nos. 3,173,579 and 3,493,146, the former showing a valve as part of the spout and the latter as a separate unit from the spout.